IsValidEmail issue

[tcoakley]

Type of issue

Code doesn't work

Description

[Enter feedback here]
The provided code is great, but it returns true for this invalid email address. me@-test.com

This regex adjustment fixes this

                return Regex.IsMatch(email,
                    @"^[^@\s]+@[^@\s-]+\.[^@\s-]+$",
                    RegexOptions.IgnoreCase, TimeSpan.FromMilliseconds(250));

Page URL

https://learn.microsoft.com/en-us/dotnet/standard/base-types/how-to-verify-that-strings-are-in-valid-email-format#example

Content source URL

https://github.com/dotnet/docs/blob/main/docs/standard/base-types/how-to-verify-that-strings-are-in-valid-email-format.md

Document Version Independent Id

fd3699bb-4881-b6b4-1275-43eed3d5f626

Article author

@adegeo

Metadata

• ID: 202e3f9f-a12a-53de-9069-fd469e3dbebc
• Service: dotnet-fundamentals

[adegeo]

Hi @tcoakley

Thank you for the suggestion. At this time we're not modifying the examples here. We've had a lot of issues opened for this article suggesting various tweaks, fixes, and improvements, to the regex. It can be endlessly expanded and overcomplicated. Because of the possible endless tweaks to the regex, we don't commit time to working on the regex and instead guide the readers with this note:

It's recommended that you use the simple (@)(.+)$ regular expression pattern to normalize the domain and then return a value indicating that it passed or failed. However, the example in this article describes how to use a regular expression further to validate the email. Regardless of how you validate an email, you should always send a test email to the address to ensure it exists.

While your suggestion starts to improve the regex, it is still technically invalid. It does correctly detect the invalid domain me@-test.com, but it also flags me@domain-test.com as invalid, but that is actually a valid domain name.